Kelly Clarkson embarrassed by tears

Kelly Clarkson was "so embarrassed" about breaking down on 'American Idol' last week.

The 33-year-old singer - who is pregnant with her second child, a brother for her and husband Brandon Blackstock's 20-month-old daughter River Rose - knew it would be emotional returning to the show which made her famous, but "didn't realise" she would get so tearful while performing 'Piece by Piece'.

She said: "I didn't realise it was gonna be that bad. And we were rehearsing that day and I just couldn't get through it."

"I came off almost in tears for a different reason because I was so embarrassed. I was like, 'Oh God, this is my final thing on 'Idol' and I could not hold it together.' I was almost losing it almost the entire song."

Kelly admitted her tears were also partly due to nostalgia, and having her family there with her.

She told talk show host Ellen DeGeneres: "My one year old [was] running around the same hallway as I was [at] 19...

"Brandon was there, my little girl was there, my little boy was turning circles in my stomach. It was nostalgic.

"It was the last time I was gonna be on 'Idol' and it's ending. I was screwed from the get-go.

"Emotionally, I was on a slip and slide from hell."

However, the 'Breakaway' hitmaker insisted she is still "proud" of herself "for making it as far as [she] did."

She added: "My husband knows me well. I came right off stage and he was like, 'Don't ruin it. Don't ruin the moment.' Because I was like, 'It was so embarrassing, oh my God. I cried the whole time.' "[route]."